The U.S. and the world population consume large amounts of hot peppers. Capsaicin, the pungent principle of hot pepper, was found in substantial mounts (up to 0.53%) in the species of the genus Capsicum. In preliminary experiments, we demonstrated that capsaicin exhibited mutagenic activitty in the Ames assay. We have also shown that the oral administration of capsaicin induced a few intestinal tumors in mice. In the present proposal we plan to: (1) determine the mutagenic activity of capsaicin, both its pure homologues and extracts of hot red pepper in the S. typhimurium assay; (2) assess the mutagenic ability of capsaicin, both its homologues and murium assay; (2) assess the mutagenic ability of capsaicin, both its homolgues and extracts of hot pepper in the hamster hepatocyte-V79 mammalian test; (3) study, by feeding experiment using semisynthetic diet in mice, the tumorigenicity of capsaicin; (4) determine by intragastric gavages the tumorigenic action of capsaicin in mice; (5) investigate in a feeding study, using semisynthetic diet in mice, the tumorigenicity of hot red (dried) pepper; (6) compare the metabolism of radiolabeled capsaicin by subcellular fractions from mouse duodenum (target tissue), liver (possible target tissue) and from lungs and colon (non-target tissues). We will use the cytochrome P-450-dependent monooxygenase and prostaglandin (H) synthase systems. Any reactive metabolites that are formed will be trapped with glutathione (GSH) and the nature of the GSH-metabolite complex will be determined. We will also: (7) assess the levels of radiolabeled capsaicin and its metabolitesin the blood, feces and urine; (8) study the ability of H3-capsaicin, its homologues and metal metabolites to interact in vitro and in vivo with DNA; and (9) synthesize radiolabeled capsaicin and dihydrocapsaicin. We will will isolate sufficient pure quantities of capsaicin and its homologues by HPLC for other investigations. These studies are designed to determine the biological effects of hot pepper and capsaicin in vitro and in invo experiments. Investigations on the mechanisms of action of capsaicin will hopefully elucidate the enzyme systems and tissues responsble for metabolism. The DNA binding studies will indicate the importance of the two potential binding sites of capsaicin molecule. Undoubtedly, naturally occurring chemical carcinogens found in the diet are probably the major factors in the etiology of important human cancers. Consequently, the consumption of hot Capsicums by the U.S. and world population may result in harmful effects.